US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
249 PM EST Thu Dec 27 2018
 
Valid Sunday December 30 2018 - Thursday January 3 2019
 
Hazards:

Heavy rain across portions of the lower Mississippi Valley, the Tennessee Valley, the Mid-Atlantic, 
and the southern Appalachians, Sunday-Monday, Dec 30-31.
Flooding possible across portions of the Upper Midwest and the southern Plains.
Flooding occurring or imminent across portions of the Southeast U.S.
Flooding likely across portions of the central Plains and the Upper Mississippi Valley.
Much below normal temperatures across portions of the Upper Midwest and northern Plains, 
Tuesday-Wednesday, Jan 1-2.
Much below normal temperatures across portions of the southern Rockies and western High Plains, 
Tuesday-Thursday, Jan 1-Jan 3.
High winds across portions of southern mainland Alaska, Monday, Dec 31.
High significant wave heights for coastal portions of the Aleutians, Sunday-Monday, Dec 30-Dec 31.
 
Detailed Summary:

As a surface low tracks across the northern Great Lakes on Monday and Tuesday, more moisture is 
expected to spread across the Southeast. This will lead to an extended period of widespread rain, 
heavy at times, from the central Gulf Coast to the southern Appalachians.  The exact location of 
the heaviest rain amounts will be dependent on the position of the frontal boundary and surface low 
track.  Some wintry precipitation may fall along the northern fringe given colder surface 
temperatures.  

A low pressure system will then track across the Pacific Northwest and northern Plains by December 
31st, bringing light snowfall.  This system will be responsible for another shot of arctic air.  
Temperatures will once again drop well below normal across portions of the Northern Plains and 
Upper Mississippi Valley on January 1st and 2nd.  High temperatures could struggle to reach the 
single digits across northern Minnesota and parts of the eastern Dakotas.

For Alaska, a deep surface cyclone is forecast to move north of the Aleutians on the 31st and 
towards the Gulf of Alaska by the 2nd.  This may result in significant waves (>20 ft) or high winds 
(>50 knots) across portions of the Aleutians and possibly into parts of the western Panhandle. 

Hamrick